Buenos Aires Research Articles

Teachers’ perspective on the use of artificial intelligence on remote experimentation

Remote Laboratories have become crucial educational resources due to their implementation in institutions that have adopted hybrid teaching models. Moreover, artificial intelligence (AI) has increasingly been used to develop educational support tools. Remote Laboratories suffer from a limitation: when students conduct experimental activities, instructors cannot always be immediately available to resolve doubts. To address this limitation, a virtual assistant was integrated into the Acid–Base Titration II Remote Laboratory. The aim of this research is to understand the perspective of chemistry teachers from the Common Basic Cycle of the University of Buenos Aires on the use of this artificial intelligence tool. For this purpose, a focus group was conducted in which a series of questions were asked before and after using the AI tool. The findings reveal that teachers perceive great potential in the combination of these technologies. Furthermore, the virtual assistant could offer personalised assistance in real time, which ensures accompaniment during the completion of the Remote Laboratory.

Accessible Non-Invasive Techniques for Museums: Extending Sustainability to Resource-Limited Institutions

This work provides a synthesis of an initial experience in the development of accessible imaging techniques and their implementation on a real case: the analysis of colonial Hispano-American paintings at the Complejo Museográfico Provincial “Enrique Udaondo” (Luján, Buenos Aires). It discusses different aspects related to the possibilities of obtaining, using, and reusing equipment and materials locally, as well as details of the ways of acquiring images for photography on site. It also provides information about the composition and conservation state of selected artworks, complementing image analysis with portable X-ray fluorescence (XRF) data, and reflects on articulated/collaborative work in situ as a methodology for transferring knowledge and skills. The project aims to contribute to strengthening Latin American sustainability by creating accessible non-invasive tools for heritage conservation institutions, highlighting the value of regional capacities to approach heritage studies from collaborative and ethical proposals that promote sovereignty and reduce dependence on external inputs.

2023 epidemic dengue fever outbreak: the experience of a pediatric hospital in the City of Buenos Aires.

Introduction. Dengue is a viral infection that may be asymptomatic or include severe manifestations. This study aims to describe the characteristics of a pediatric population during the epidemic outbreak in 2023. Population and methods. This cross-sectional study included patients with probable or confirmed dengue fever who were seen from March 13, 2023, to May 19, 2023, in a pediatric hospital in the Autonomous City of Buenos Aires. Results. A total of 112 patients were included. The median age was 12 years; 58% were male. Seventy-six percent of them came from the City of Buenos Aires. Twenty-five percent had cohabitants with symptoms compatible with a suspected case. The most frequent clinical manifestations were fever, headache, retro-ocular pain, myalgia, and arthralgia. The most frequent laboratory alterations were leukopenia (65%) and elevated transaminases (60%). Twenty-one percent (24/112) presented alarm signs and required hospitalization. Leukopenia, plateletopenia, and elevated transaminases were associated with the presence of alarm signs. RT-PCR was detected in fifty-three patients; serotype 2 was the most frequent. Twenty-one patients had positive NS1 tests, 18 patients had positive IgM, and 20 patients with clinical and epidemiological links were assumed to be probable dengue cases. There were no cases of severe dengue. Conclusion. Early clinical suspicion and recognition of laboratory parameters associated with alarm signs are essential for an adequate approach to the disease and early supportive treatment during dengue infection.

Management of patients with locally advanced rectal cancer in the total neoadjuvant therapy (TNT) era: Experience from Argentina.

85 Background: In the last years a paradigm shift has changed the way we manage non metastatic rectal cancer. The varied options within TNT have gradually been adapted in our country. This study aims to depict the strategies implemented. Methods: A prospective and retrospective observational study was performed from 2020 to 2024 including stage II-III rectal cancer patients treated at three centers in Buenos Aires, Argentina. Data was extracted from medical records. Results: 68 patients were included in the analysis. Median age was 59 years (IQR 48–71). 72% were male. 88% (60) had stage III disease, and 12% (8) stage II. Geriatric assessment was performed in 7 of 19 patients aged over 70 (5 frail). All patients were staged with high resolution MRI and discussed in multidisciplinary tumor board. Mismatch repair was assessed in 72%(49) of patients, only one had MLH1 deficiency. 79%(54) patients received TNT: 22%(12) short course vs 78%(42) long course radiotherapy; 24%(13) induction vs 76%(41) consolidation chemotherapy. Preferred chemotherapy regimen was CAPOX both in induction and consolidation chemotherapy (69.7% and 63.4%, respectively) Despite small numbers non significant differences in risk factors were found between TNT vs non TNT groups (Table). We registered 13 Grade 3-4 toxicity events: 3 in induction chemotherapy, 7 in consolidation and 3 in radiotherapy. Clinical complete response was achieved in 25.9% of TNT (11 consolidation, 3 induction) and 7.1%(1) of non-TNT (p=0.25). Watch and Wait was employed in 9 patients in TNT and 1 in non TNT group. 40 patients underwent surgery in the TNT and 11 in the non-TNT group; complete pathological response was reached in 17.5% (7) and 9% (1), respectively. Overall relapse rate was 19.14% (13): 2.94% (2) local and 16.2% (11) systemic. (TNT: 1.85%(1) local vs 18.5%(10) metastatic; nonTNT: 7.14%(1) both local and metastatic) p=0.4. At a median follow-up of 20 months (IQR 15–32 months), 2-year progression-free survival (PFS) rate was 87% (95% CI: 38–98%) in the non-TNT group and 78% (95% CI: 61–88%) in the TNT group. Conclusions: This study highlights the feasibility of worldwide adoption of TNT. We describe the preferred regimens and results of TNT in three high volume centers in Argentina. Long course radiotherapy and consolidation treatment with CAPOX are the predominant strategies. Non operative management is routinely offered to complete responders. Our efficacy results are comparable with published literature. Comprehensive geriatric assessment is recommended but still partially applied. In line with recent findings MMR testing has been widely adopted as an initial workup parameter. TNT %(n=54) non-TNT %(n=14) p T4 disease 26 (14) 21 (3) 0.99 N2 37 (20) 29 (4) 0.75 EMVI positivity 49 (26) 18 (3) 0.16 Circumferential resection margin <1 mm 29.6 (16) 28.57 (4) 0.23 Low-lying tumors 33 (18) 43 (6) 0.54

Demographic and Genetic Impact of the 1742–1743 Plague Epidemic in Córdoba, Argentina: A Bioanthropological Perspective

Background: This study investigates the demographic, genetic, and socioeconomic impact of the 1742–1743 plague epidemic on Córdoba, a key region within the Viceroyalty of Peru. The research focuses on the epidemic’s influence along the Royal Road (Camino Real), the main route connecting Buenos Aires and Lima, addressing a historically overlooked period with a multidimensional approach. Methods: Historical records of deaths, baptisms, and marriages from the Córdoba Archbishopric Archive were analyzed using techniques from historical demography and bioanthropology. Variables such as endogamy, exogamy, average marital distance (AMD), and consanguinity coefficients were evaluated. Results: The findings reveal a significant increase in endogamy (75–82%) and a peak exogamy index of 375 during the 1740–1744 cohort. The AMD rose to 705 km during the epidemic, indicating a shift toward marriages involving individuals from more distant regions. The total consanguinity coefficient (Ft) reached 0.00056, with the non-random component (Fn) driving this increase, suggesting heightened genetic isolation. Conclusions: The 1742–1743 plague epidemic intensified genetic isolation and consanguinity, potentially increasing homozygosity and the prevalence of recessive conditions. These changes highlight the epidemic’s long-term impact on Córdoba’s genetic diversity and demographic patterns within the colonial context.

Groundwater hydrodynamics of the sandy coastal aquifer of southwestern Buenos Aires, Argentina. Punta Alta - Monte Hermoso sector

Groundwater hydrodynamics of the sandy coastal aquifer of southwestern Buenos Aires, Argentina. Punta Alta - Monte Hermoso sector

P-1206. Dengue Epidemic Outbreak 2023-2024: is it here for good? Experience in a Tertiary Care Pediatric Hospital in Buenos Aires, Argentina

Abstract Background Between epidemiological weeks (EW) 1 and 13 of 2024, the Region of the Americas reported 4,820,955 suspected dengue cases, triple the count from 2023. Argentina ranked second with 379,341 cases, a fourfold increase from the previous season. Our aim is to describe the behavior of dengue in a pediatric population during 2023 and 2024 and compare the characteristics of the latest two dengue outbreaks in Argentina. Methods Two cross-sectional studies were conducted in a children’s hospital in Buenos Aires City. Clinical, epidemiological, laboratory, and follow-up data were recorded for patients < 18 years with confirmed dengue, according to PAHO definitions. The first season period included from March to May 2023 (EW 11 to 20) and the second from January to April 2024 (EW 2 to 15). Results A total of 1145 suspected cases were attended. 565 (49%) patients with confirmed dengue were included. Median age: 11 years (IQR 9-14), 308 (54%) being male. Most common symptoms: fever (100%), median duration of 4 days (IQR 3-5); headache/retro-orbital pain (88%); myalgias (75%). 188 patients (33%) exhibited warning signs, the most common: mucosal bleeding, persistent vomiting and severe abdominal pain. 396 patients had leukopenia (71%) and 346 had elevated liver enzymes (62%). Thrombocytopenia (< 100,000/mm3) was found in 131 patients (24%). Significant differences were observed when comparing warning signs: more mucosal bleeding in 2024 (p< 0,001), and more abdominal pain in 2023 (p=0,023). Regarding diagnosis, 495 (88%) patients were confirmed by detectable RT-qPCR, serotype 2 predominated (57%) and was significantly most frequent in 2023 (p< 0,001). 70 (12%) patients had positive NS1 antigen enzyme immunoassay. 86 patients (15%) required hospitalization. 5 cases (0,8%) of severe dengue. No deaths occurred. Conclusion Timely and precise diagnosis, along with proper categorization of severity criteria, are crucial during dengue infection. One third of patients had warning signs. Despite serotype 2 being the most common during the 2023 outbreak, which is often linked with severe dengue, the hospitalization rate was the same in both periods. The new quadrivalent vaccine available could be an important tool to decrease the number of patients in our region. Disclosures All Authors: No reported disclosures

P-187. Clinical Profile of Atypical Manifestations of Dengue Fever and Severe dengue fever in children in Argentina

Abstract Background The clinical presentation of dengue fever has a wide spectrum; unussual manifestations have been reported and with the rising disease burden, atypical manifestations are also on rise, but are underreported and often missed due to the lack of awareness among health care professionals. In Argentina we are witnessing the largest historical outbreak of dengue in 2024. The objective of the study is to study the clinical profile and outcome of atypical and severe manifestations of dengue fever in children. Methods All children (0–18 y of age) confirmed as dengue fever at a tertiary care hospital at Buenos Aires, Argentina between January 2023-April 2024 were reviewed retrospectively from hospital case records. The diagnosis was confirmed by NS1 antigen/IgM based ELISA or inmunocromatography test, PCR. The data was analyzed using EpiInfo 7.2 Results Out of 213 children admitted with dengue fever, 7 % had severe dengue. Atypical manifestations were seen in 37 cases ( 17 %). Mean age of presentation was 6.5 (5.2) y. M: F ratio was 1.1:1. The common manifestations of severe dengue infection were shock (80 %), bleeding (20 %) and multi organ dysfunction (6 %). The most common atypical manifestations of dengue fever were hepatitis (19%), seizures (8 %), acalculous cholecystitis (8%), myositis (8%),pneumonia (8%), febrile infant without focus (8%), febrile diarrhea (19 %). The other atypical manifestations present were ataxia, meningitis, acute respiratory distress syndrome (ARDS), myocarditis, lymphadenitis, prolonged fever, pericardial and pleural effusion. There was one death (0.4 %). Conclusion The atypical manifestations of dengue fever are no more a rare entity. Clinicians should have a high index of suspicion and surveillance for atypical manifestations of dengue fever as lack of timely detection and management could be fatal. Disclosures All Authors: No reported disclosures

P-1548. Risk Factors for Escherichia Coli Resistance to First-line Antibiotics in Urinary Isolations in Children

Abstract Background There is concern about the increase in antibiotic resistance to Sulfamethoxazole/trimethoprim (SMX/TMP) in urinary tract infections (UTI) in children. There is limited evidence on whether there are associated risk factors for this resistance. The Objective of our investigation is to evaluate if there is an association between E. Coli resistance to (SMX/TMP) and previous episodes of UTI, prophylaxis or antibiotic treatment, hospitalizations, urinary tract disorders, age and sex. Characteristics of children with SMZ-TMP-resistant E. Coli isolates compared to the control group Methods retrospective study that evaluated 117 medical records from Nephrology service of Elizalde Hospital, in Buenos Aires , Argentina from 1/1/2018 to 12/31/2018. The sample was divided into two groups. A control group (68 patients) with E. coli sensitive to SMX/TMP in urine isolations and a group of cases (49 patients) with resistant isolates. Risk factors were considered and association was evaluated by Chi test, OR calculation with 95% confidence intervals. Binary logistic regression was performed . Significance 0.05. Age was dichotomized into older and younger than 2 years old Results Sex showed no association with resistant insulation. Patients older than 2 years old, were associated with resistant isolates (p = 0.01). Patients with hospitalizations were 3 times more likely to have a resistant insulation (p = 0.001). Alterations in the urinary tract increased 3.9 times the risk of resistant isolates (p < 0.0001). Greater resistance was observed in those with recurrence of infection (p < 0.0001). The multivariate analysis indicated that those patients with prophylaxis had an 83 times greater risk of presenting isolates resistant to SMX/TMP than patients without this risk factor (OR 83.47, 95% CI 12.6 – 552.21) Conclusion Prolonged use of antibiotics and receiving antibiotic prophylaxis were the only factors independently associated with the finding of SMX/TMP-resistant E. Coli Disclosures All Authors: No reported disclosures

The photochemical inheritance of Eduardo Lissi and Juan Grotewold and the intersystem crossings with otherinheritances.

In 1963, Eduardo Lissi and Juan Grotewold started a chemical kinetics and photochemistry group at the School of Sciences at the University of Buenos Aires (Facultad de Ciencias Exactas y Naturales, FCEN, UBA). Political circumstances in Argentina and in Chile were a great determinant of the evolution, dispersion, and re-encounters of the group members. The initial graduate students in the group developed their own research groups working in various Countries and on a variety of projects. We relate the story of the strong interactions with each other of the original group as well as the cooperations and synergy (Intersystem Crossings) of Lissi and Grotewold and of their descendants with other research groups, mainly (but not only) in Latin America. A strong network of partnerships, friendships, and fruitful collaborations between the kineticists, photochemists, and photobiologists in Argentina, Chile and Brazil has evolved from the initial steps in the 1960s.

P-1990. Out-of-Hospital Care Setting in a Febrile Emergency Unit of Suspected Covid 19 Patients

Abstract Background In 2019, a new infection was reported in China. This coronavirus was named SARS-COV-2, causative of the 21st-century pandemic, COVID-19. Health systems adopted different strategies to cope with it. Objective to describe the clinical-epidemiological characteristics of COVID-19 in children seen at an Emergency Febril Unit (UFU). Demographic and epidemiological characteristics of children treated at EFU of Pedro de Elizalde Children's Hospital (n = 952) Methods Cross-sectional study in patients under 18 years of age tested for SARS-COV-2 between April 1 and June 30, 2020. All epidemiological records made at the time of consultation and the result of the Polymerase Chain Reaction (PCR) test of these patients, either by suspicion of COVID-19 or epidemiological isolation criteria, were included. Patients whose samples had been taken for SARS-COV-2 determination outside the initial time of consultation or whose epidemiological records were incomplete or did not meet the established inclusion criteria were excluded. The diagnosis of COVID-19 was made using the PCR technique for SARS-COV-2 in nasopharyngeal secretions obtained by nasopharyngeal swab or aspirate. The following variables were recorded: age, gender, place of residence, history of close contact, history of history of close contacts, travel history and comorbidities, history of institutionalization and PCR result. Presentation of symptoms: Frequency Results 1,104 patients were admitted to the UFU and tested due to suspected COVID-19. 152 patients had to be excluded due to insufficient data. Of the 952 patients tested, 22.6% had a detectable result, and 71.2% of them reported close contact with confirmed cases. The mean age was 5.9 years. The 55.4% were male and 99.3% lived in the Metropolitan Area of Buenos Aires. 72.8% of the patients tested had symptoms. The time of delay in consultation was 2.17 days. 25% of the children had comorbidities. Conclusion The availability of the UFU facilitated access and optimized the care circuit in response to demand. Children with a history of close contact and those symptomatic showed more frequently a detectable result for SARS-COV-2. Disclosures All Authors: No reported disclosures

ІСТОРІЯ ВИНИКНЕННЯ ТА ПЕРСПЕКТИВИ РОЗВИТКУ ПЛЯЖНОГО ГАНДБОЛУ

Every year more and more new sports appear in the world, which are rapidly developing and becoming popular. Among them is beach handball. Due to its spectacularity, it attracts more and more people and arouses great interest around the world. Scientific research is necessary for its development, as it is an under-researched sport, although the number of studies has recently increased. The purpose of the study. To study the history of origin and prospects of development of beach handball. Research methods: in accordance with the purpose of the study, the methods of theoretical analysis and generalization of scientific and methodological literature and information resources of the Internet were used. Results of the research and their discussion. The first idea about the creation of beach handball arose in the Italian Olympic committee in 1990, which tried to create a kind of handball on the sand, based on the success of beach volleyball. On June 20, 1992, beach handball was first played on Isola di Ponza, a small island in southern Italy. The idea of beach handball as a sport was realized gradually, over many years, by players and coaches. A huge step in the development of the discipline was the participation of beach handball in the Youth Olympic Games in 2018 in Buenos Aires (Argentina). And this year, beach handball made its debut at the Summer Games in Paris, where the world stars of the sport were present within the framework of an exhibition event. Conclusions. Beach handball originates from classic handball. Today, beach handball is represented at almost all sporting events of global importance, which indicates the growing popularity of the sport in the world. The main goal is to be in the official program at the Olympic Games and become an Olympic sport.

Detection and selection of dye-degrading bacteria from surface waters with different degrees of contamination

ABSTRACT Biodegradability and resistance from indigenous bacterial communities to dyes were tested using samples from both polluted and unpolluted surface waters in Buenos Aires. Five dyes were selected for the study: Acid Black 210, Direct Orange 39, Malachite Green, Gentian Violet, and Alizarin Red. Water quality was assessed by measuring chemical oxygen demand, biochemical oxygen demand, and both Escherichia coli and enterococci counts. Biodegradability was tested using a respirometric method, while resistance was assessed by determining the minimum inhibitory concentration (MIC). No bacterial strains capable of degrading the dyes as the sole carbon source were isolated from the respirometric tests. However, from the MIC tests, 28 strains capable of dye discolouration were identified, using nutrient broth as a supplement. Two of them were able to degrade Malachite Green and Acid Black 210 at a concentration of 50 mg L−1 in less than 24 h and with an efficiency greater than 87%. These strains were identified as Aeromonas sp. and Shewanella sp. through MALDI-TOF/MS and 16S rRNA gene sequencing. The determination of biodegradability and resistance can be used to enhance the characterization of watercourses. Furthermore, this methodology provides a means to isolate biodegrading bacteria that could be applied in effluent treatment processes.

Impact of the 1742–1743 Plague Epidemic on Global Excess Deaths and Social Dynamics in the City of Córdoba and Along the Camino Real Between Buenos Aires and Lima

The 1742–1743 plague epidemic profoundly impacted populations along the Camino Real, the main colonial trade route connecting Buenos Aires and Lima, with Córdoba, Argentina, as a critical focal point. This research examines the multidimensional repercussions of the epidemic, emphasizing its demographic, social, and economic consequences. Utilizing parish records as primary sources, this study quantifies the excess mortality, revealing a dramatic increase, with death rates in Córdoba peaking at 12 times the pre-epidemic average in May 1743. Marginalized groups, particularly enslaved and Indigenous populations, were disproportionately affected, which exacerbated existing social inequalities. Through a comprehensive analysis of historical data, this study contributes to understanding epidemic responses in colonial Latin America, illuminating how public health crises intersect with demographic and socio-economic structures. The findings provide insights that are relevant to contemporary public health perspectives on crisis management and resilience, highlighting how historical epidemics offer valuable understanding into the social dynamics of health emergencies.

Argentina–Qatar: From unlikely partners to a developing partnership (2011–23)

The question that guides this research is: How has the link between Argentina and Qatar evolved and what factors explained this evolution in the period between 2011 and 2023? As regards the methodological design, the work rests on a qualitative design, based on the collection and analysis of data from both primary and secondary sources. Among the former, unstructured interviews with key informants stand out. That said, the investigation shows that the Administrations that have succeeded one another in power in Buenos Aires between 2011 and 2023 have driven political–diplomatic relations with Doha, particularly as a result of the Argentine interest in strengthening economic–commercial ties with Qatar. Ultimately, the search to diversify business partners, to receive investments and to increase the volume of trade explains the deepening of these ties. Especially considering that Qatar is perceived as a potential partner based on its own need to ensure food security, something that Argentina may benefit from. In terms of the prospects of the bilateral relationship, it is clear that Javier Milei’s government is interested in continuing to cultivate its ties with Qatar. In fact, there is still insistence on the need to deepen economic and financial ties. However, the impact that the conflict in the Middle East will have on the bilateral relationship remains to be seen, even more considering Argentina’s alignment with the State of Israel and President Milei’s discourse, which has associated Islam with terrorism.

P0278 Healthcare resource utilization by patients with Difficult-to-Treat Inflammatory Bowel Disease in Latin American Countries.

Abstract Background Latin America is a geographical region with heterogeneous access to health care and advanced drug therapies (ADTs) required for Inflammatory Bowel Disease (IBD) management, especially for more difficult cases.1,2 We aimed to characterize the use of healthcare resources for IBD management, namely for difficult-to-treat IBD (D2T-IBD), in this region.3 Methods Observational study with secondary data from four LatAM registries: EPILATAM-IBD (Epidemiologic characterization of Inflammatory Bowel Disease in Latin America: Multicentric Study) with patients from 9 LatAM countries, the GEDIIB – Brazilian Organization of Crohn’s Disease and Colitis national registry, and two single-centre registries in Argentina, in Buenos Aires and Córdoba. This analysis included adult patients diagnosed with ulcerative colitis - UC, Crohn’s disease- CD, or unclassified, and at least one prescribed IBD drug. Patients were classified with D2T-IBD if having failed ≥ 2 mechanisms of action of ADTs, chronic antibiotic-refractory pouchitis, postoperative CD recurrence after ≥ 2 intestinal resections, or complex perianal CD. Characteristics of D2T and non-D2T patients were compared with Mann-Whitney test, and chi-square or Fisher’s exact tests (p<0.05). Results Of 6314 eligible patients (55.2% UC, 43.9% CD, and 0.9% unclassified), 5598 had criteria information, and 742 (13.3%) were classified as D2T. The proportion of D2T-IBD was higher among CD patients (30.2% vs 1.6% of UC patients; p<0.001). Patients with D2T-IBD were statistically significantly diagnosed at a younger age than non-D2T patients, had a longer time until diagnosis, and more patients were followed in private healthcare setting – Table 1. D2T patients had statistically significantly higher incidence and mean number of surgeries (73% vs. 10% of non-D2T patients) and hospitalizations (49% vs. 37%) – Table 1. They also received more drugs since diagnosis (36% received 4+ drugs), namely ADTs (19.5% received 3+ ADTs) – Table 2. Among D2T patients, 64% were prescribed immunomodulators and 83% ADTs since diagnosis. The percentages prescribed 2 or more anti-TNFs (28%) and ADTs other than anti-TNF (anti-integrin: 14%, anti-interleukin: 19%, Janus kinase inhibitors: 4.2%) were also higher among D2T patients. Conclusion D2T-IBD was associated with a significantly higher incidence of surgeries and hospitalizations, resulting in a higher burden for healthcare systems. In addition, D2T patients required more ADTs, both in the number of different treatments as well as classes other than anti-TNFs. D2T patients represent a relevant unmet medical need in IBD in the Latin America region.

Digestive and metabolic profile of the resident population of the silverside Odontesthes argentinensis from Mar Chiquita Coastal Lagoon (Buenos Aires, Argentina).

The knowledge about the occurrence and biochemical characteristics of key digestive enzymes is crucial for an enhanced understanding of the dietary ecophysiology of the species. On the other hand, integrative studies on digestive physiology and on tissue content of glycogen, glucose, lipid and protein in groups of ecological and economic importance are currently limited. In this work, we determined the occurrence and biochemical characteristics in intestine of key digestive enzymes activities as indexes of the ability to digest different dietary substrates and of functional differentiation for digestion/absorption of nutrients along with the intestinal coefficient as index of dietary habit and digestion efficiency in adults of Odonthtestes argentinensis inhabiting Mar Chiquita Coastal Lagoon (Buenos Aires, Argentina). Furthermore, to identify storage sites, glycogen, triglycerides and protein content in different tissues were also analyzed. The presence and biochemical characteristics of amylase, maltase, sucrase, lipase, trypsin and aminopeptidase-N activity in intestine, as well as the tissue content of glycogen, triglycerides and protein suggests that adults of O.argentinensis exhibit an adequate digestive battery to potentially perform complete hydrolysis of various dietary substrates and capacity for storage and/or utilization of energy reserves. Our study provides novel insights into the digestive/metabolic traits in adults of the resident silverside O. argentinensis from Mar Chiquita Coastal Lagoon.

Potential of Ionizing Radiation Application for Reducing Environmental Risks Related to Solids Residues

The enormous amount of solids residues and related cost for a suitable disposal have increased in megacities as São Paulo and Buenos Aires. Inovative technologies may be used in order to face managing progams with inovative techniques for for recycling or recover of materials. Gamma radiation was applied in laboratory scale for two different types of residues: fungi control in vehicular air filters, and for rat bedding waste (RBW) disinfection. Both materials may be used after irradiation and the radiation doses required will be discussed. Part of experiments carried out in Argentina evidenced the suitable use of vermicomposting for growing Calendula officinalis. Radiation doses from 10 kGy up to 30 kGy were tested for controlling microorganisms during the projects and were very effective. For filters disinfection experiments, DNA sequencing analysis for the fungi that survived after irradiation not only confirmed the presence of Penicillium, Fusarium and Aspergillus (toxigenic), fungi but also improved the data: the contamination included Aspergillus niger, Aspergillus flavus, Penicillium glabrum specie complex and Fusarium incarnatum-equiseti specie complex.

Distribution, abundance, and size structure of the Pacific cupped oyster Magallana gigas in northern Patagonia

In the 1980s, the Pacific oyster Magallana gigas (Thunberg, 1783) was deliberately introduced in the southern region of the Province of Buenos Aires (Bahía Anegada, BA), Argentina. In 2004, its presence expanded 80 km south of the Río Negro estuary along the coast of El Cóndor (EC). Although oysters have demonstrated dispersal capability, there is limited data as regards the EC population since 2011. This research focusses on the present M. gigas population encompassing distribution, abundance, and size structure along a 180-km coastal line from EC to San Antonio Este (SAE). Subsequently, we compared these data with those for the BA population. The presence of M. gigas in the Province of Río Negro was detected in four sites: three of them near the Río Negro estuary (EC, Piedras Verdes PV, and El Pescadero); and the last one in San Antonio Bay. Estimated average abundances near the estuary were lower (range 1.8 10-3 ± 0.6 10-3 and 9 10-2 ± 3.4 10-2 ind. m-2) than BA (105 ± 2 ind. m-2). Presence in SAE was only limited to one site and three adults M. gigas. The BA oyster population exhibited a multimodal distribution, with a significant number of recruits, whereas the PV site displayed a trimodal structure dominated by large specimens. In EC, owing to the limited number of individuals, modal components were less discernible, but small oysters predominated. The current abundance of M. gigas in EC was considerably lower than that in 2011, indicating a population decline. Despite this, the presence of juvenile oysters suggests recent recruitment, emphasizing species resilience. These results show that M. gigas faces challenges when attempting to establish itself in this specific region. Studying the underlying causes would help to understand the factors that limit the expansion of a species considered to be a global invader.

Pedagogies of awareness and subterfuge: The interpretive labor of domestic worker organizing in Buenos Aires

AbstractIn 2013, Argentina passed Law 26844, transforming domestic workers' status from “servants,” with almost nonexistent labor rights to “workers,” with rights virtually equal to all other workers under the law. Since then, domestic workers' legal equality has stood against the intersectional inequalities they still endure vis‐à‐vis their employers and that challenge advancement to their labor rights. Based on ethnographic research conducted in Buenos Aires between 2016 and 2018 with domestic workers' rights advocates, this article investigates how they contend with these challenges. It examines the interpretive labor they engage in as they encourage workers to undertake situated strategies to advance their labor rights. These strategies consist of increasing workers' knowledge of their rights while, simultaneously, encouraging them to execute dissembling practices to claim and access them. These dissembling practices allow workers to perform the appropriate behaviors according to intersecting master categories of social differentiation in a context of systemic intersectional inequality. Concurrently, they enable workers to avoid direct confrontation with their employers, thus helping them to enforce their rights without jeopardizing their means of subsistence. Through these pedagogies of awareness and subterfuge, advocates create a space in which the law can be effected, promoting workers' agency without compromising their livelihoods.